Temperature-relay



Dec. 16, 1952 H. VAN TQORN' 2,622,170

MPERATURE-RELAY Filed Oct. 19, 1949 PIC-5.2

Patented Dec. 16, 1952 UNITED STATES 'E" FFl-CE assignor to N. V. Koninklijke Metaalwarenfab rieken v. h. J. N. Daalderop & Zonen, Tiel, Netherlands Application October 19, 1949, Serial No. 122,305 In the Netherlands February 4, 1949 8 Claims.

The present invention concerns a temperature-relay, called Thermostat, of a simple and robust construction, consisting of few elements and which can close and reopen a circuit immediately.

The relay according to the invention consists of a magnet with two poles, while opposite each pole an armature of soft iron is secured, both armatures being mounted on one end of a bimetal reed, the other ends being connected in mutual thermal contact and with a source of current and the two reeds being interconnected by a rod so that one of the reeds in the initial cold position of the relay is pressed with pretension against the magnet and by heating the two bimetal reeds are bent in the same direction, i. e. one reed by removing itself from and the other by approaching the magnet.

Other features and advantages will appear from the following description.

The drawings represent a schematic example, not limiting the various forms of execution of the invention.

1 represents a plan view of one form of execution;

Fig. 2 gives a view in detail of the magnet; and

Fig. 3 shows a modification of the magnet shown in Fig. 1.

Referring to Fig. 1 it can be seen that with I is shown an anisotropic magnet, mounted in a box 2 of soft iron, consisting of two parts 2a and 2b, at the same time-forming the two poles. On both sides of this magnet the two bimetal reeds 3 and 4 are arranged, each of them being fitted with armatures of soft iron 5 and 6. In dotted lines the position of the two reeds in cold state is shown in Fig. 1, if the magnet were not placed between the two reeds. In this way the armature 6 is pressed with pretension against the magnet I.

In Fig. 2 is shown a section of the armature. It can be seen, that on this armature 6 a contact l of argentan is mounted, which sticks :0.1 mm. but of the inner face of the armature.

In the slot of the box 2 a same contact 8 is arranged (Fig. 3) hereby preventing the armature 6 from sticking.

The other ends of the reeds are fixed on a block of copper 9 fitted with a contact screw H] for the connection of this block with a pole of an alternate current-circuit (not drawn). The reeds 3 and 4 are interconnected by a bar H, fixed on the reed 4, but being able to slide in a slot of the reed 3. In order to limit the deflection of the reeds 3 and 4 a strap I4 is arranged.

Th reeds 3 and 4 are formed in such a way that when being heated they will bend in the same direction, while the reed 4 is moved from the magnet and the reed 3 towards the magnet.

The reed 4 is formed so that at a temperature of 85 C. it has obtained such a tension that it disengages itself from the magnet taking along with it the reed 3, which is pressed against the other pole of the magnet. So the contact 12 and I3 fixed respectively to the bar II and the other pole of the circuit are removed from each other and the current is interrupted. The temperature of the water will fall from 85 to C. By this cooling the reed 3 has obtained a tension which removes it from the magnet immediately, interrupting the contact with the magnet.

The box of the magnet 2 and the block 9 are fixed on' a foundation plate of isolating material. The contact I3 is isolated from the box 2 (2a and 2b).

The operation of this device is as follows:

In the cold condition of the device the parts have the position shown in full lines in Figure 1, the electric circuit being prepared by the closure of the contacts l2 and [3. If a current flows in the circuit the bimetallic strips 3 and 4 are both heated because they are arranged parallel.

with each other in the circuit. By the heating of the bimetallic strips 3 and 4 the latter are subjected to a bending force which, however, they are prevented from following by the armature 6 cooperating with the pole shoes 2a; 279' of the magnet. Only after the temperature of the bimetallic strips 3, 4 exceeds a predetermined value the armature 6 is suddenly displaced toward the stop arranged on the strap l4 opposite to th armature 6 whereas armature 5 suddenly approaches the magnet and comes in touch with the pole shoes 2a, 2b across the gap between the latter. It should be understood that the lines of force of the magnet I are closed in the position shown in Figure 1 through the pole shoe 2a, armature 6 and pole shoe 2b whereas on the opposite side practically no lines of force are present. If, however, armature 6 is removed from the magnet and armature '5 approached to the magnet under the influence of the bimetallic strips 3 and 4, the lines of force are closed through pole shoe 2a, armature 5 and pole shoe 2b, the opposite side of the magnet system being practically free of the lines of force. In consequence thereof the electric circuit is interrupted at contacts l2, [3 so that the bimetallic strips 3, 4 are cooled and when the temperature of the same reaches a predetermined lower value, the armature 6 approaches suddenly once more the pole shoes 2a, 2b and the armature 5 is removed from the same. In this way the magnet system and the armatures 5 and 6 define the closing and opening of the electric circuit at well defined temperatures. The contacts 1 and 8 prevent a sticking of the armatures 5 or 6 to the pole shoes by introducing a small air gap between the armatures and the pole shoes, this air gap being not shown in Figure 1 for the sake of clearness.

I claim:

1. In a temperature control device, a permanent magnet and pole assembly forming at least one gap in the magnetic flux path; two elongated flexible members, one end of one member being rigidly connected to one end of the other member; two armatures carried by said members and adapted to alternately close said gap at two spaced positions, respectively, said two elongated flexible members being temperature-responsive so as to generate a relative movement between themselves and said permanent magnet and pole assembly; and control means actuated by said relative movement.

2. In a temperature control device, a permanent magnet and pole assembly forming at least one gap in the magnetic flux path; two elongated flexible members, one end of one member being rigidly connected to one end of the other member; means slidably connecting said two members between two limits; two armatures carried by said members and adapted to alternately close said gap at two spaced positions, respectively, saidtwo elongated flexible members being temperature-responsive so as to generate a relative movement between themselves and said permanent magnet and pole assembly; and control means actuated by said relative movement.

3. In a temperature control device, a permanent magnet and pole assembly forming at least one gap in the magnetic flux path; two elongated flexible members, one end of one member being rigidly connected to one end of the other member; a rod rigidly connected to one of said members and slidably engaging the other of said members between two stops; two armatures carried by said members and adapted to alternately close said gap at two spaced positions, respectively, said two elongated flexible members being temperature-responsive so as to generate a relative movement between themselves and said permanent magnet and pole assembly; and control means actuated by said relative movement.

4. In a temperature control device, a permanent magnet and pole assembly forming two gaps in the magnetic flux path; two bimetallic reeds; an element connected to one end of said reeds, said bimetallic reeds being arranged so that their free ends tend to move in the same direction in response to a change in temperature; two armatures carried by said reeds and adapted to alternately close said air gaps at two spaced positions,

Trespectively, depending on the temperature; and

control means actuated by the movement of at least one of said reeds.

' 5. In a temperature control device, a permanent magnet and pole assembly forming at least one gap in the magnetic flux path; two elongated flexible members, one end of one member being rigidly connected to one end of the other member; two armatures carried by said members and adapted to alternately close said gap at two spaced positions, respectively, said two elongated flexible members being temperature-responsive so as to generate a relative movement between themselves and said permanent magnet and pole assembly and an electric circuit controlled by said relative movement.

6. In a temperature control device, a permanent magnet and pole assembly forming at least one gap in the magnetic flux path; two elongated flexible members, one end of one member being rigidly connected to one end of the other member; two armatures carried by said members and adapted to alternately close said gap at two spaced positions, respectively, said two elongated flexible members being temperature-responsive so as to generate a relative movement between themselves and said permanent magnet and pole assembly; an electric control circuit; a first contact in said circuit carried by said magnet and pole assembly; and a second contact in said circuit carried by one of said flexible members and adapted to make contact with said first, contact when said flexible member closes said gap.

7. In a temperature control device, a permanent magnet and pole assembly forming at least one gap in the magnetic flux path; two elongated flexible members, one end of one member being rigidly connected to one end of the other member; two armatures carried by said members and adapted to alternately close said gap at two spaced positions, respectively, said two elongated flexible members being spring-loaded and temperature-responsive so as to generate a relative movement between themselves and said permanent magnet and pole assembly; and control means actuated by said relative movement.

8. In a temperature control device, a permanent magnet of anisotropic metal; two U-shaped pole pieces forming an air gap therebetween oppositely arranged on said magnet and projecting beyond the sides of the magnet; two elongated flexible members, one end of one member, being rigidly connected to one end of the other mem- CORNELIS HENDRIK VAN 'IOORN.

REFERENCES CITED The following references are of record in'thc file of this patent:

UNITED STATES PATENTS Date- Number Name 1,798,854 Stachwell Mar. 31,19.

. 2,030,933 Persons Feb. 18,1936 2,143,085 Persons et a1. Jan. 10, 1939 2,451,535

Clark Oct. 19, 1943 

